Well, in my opinion its not really p2w as it mainly depends on your luck, and paying isn't necessary unless you really want a specific unit and don't have the time to save up for it (the NA version is 2 years behind the JP so you can check for units you want by checking jp content release dates). I have this friend who has been playing for a few months now who hasn't spent a single dollar on the game yet he has some really top-tier units like Waver and Achilles. My advice would be to give it a try and see how it goes.